Honest numbers on sports betting.
+EV Bets is an independent lab that studies how sportsbook prices behave. We write down what would count as an answer before we run the analysis, say what we already knew, and publish what we find either way.
Study #1
How long does a +EV flag last at a sportsbook?
We followed 728 +EV flags our model raised on moneyline bets at DraftKings and FanDuel. The median lasted between 15 minutes and about an hour. We left out spreads and totals after finding a bug in our own scanner; the study page explains it.
More than 24h before kickoff (n=423)
Within 2h of kickoff (n=31)
How every study is run
These rules are what make a result worth reading, including the ones that come out inconclusive.
- Pre-registered
- The claim, the metric and the threshold that decides it are written down before the analysis is run.
- Nulls published
- A study that fails or comes out inconclusive is published the same way as one that succeeds.
- Aggregates only
- No game-level data and nothing to bet on: each study describes what was measured, in totals.
- Data included
- Every study links to the aggregate data behind it, free to reuse with credit.
Free calculators
The arithmetic behind every price. No account needed.
-110
American
1.909
Decimal
10/11
Fractional
52.4%
Implied probability
One price, four ways to write it.
Open the odds converter
- Odds converter
Switch a price between American, decimal and fractional odds.
- Implied probability
See the win chance a price implies.
- EV calculator
Work out a bet's expected value from its price and your probability.
- Vig calculator
Measure the bookmaker's margin in a two-way or three-way market.
- Kelly calculator
Size a stake from your edge and your bankroll.
- Parlay calculator
Combine legs into one price and payout.
- Hedge calculator
Work out the stake that locks in a result.
Start with the basics
Plain-English guides to how odds, the vig and expected value actually work.
- What is expected value?
- How betting odds work
- What the vig costs you
- Closing line value
- Why most +EV bets still lose
- Bankroll management